1. Field of the Invention
The present invention relates to heat dissipation devices, and more particularly to a heat dissipation device which incorporates a vapor chamber and a plurality of heat pipes.
2. Description of Prior Art
During operation of many heat generating devices such as central processing units (CPUs), large amounts of heat are produced. Such heat must be quickly removed from the heat generating device, to prevent the heat generating device from becoming unstable or being damaged. Typically, a heat dissipation device is attached to an outer surface of a heat generating device to remove heat therefrom.
Referring to FIG. 5, a conventional heat dissipation device comprises a chassis 2 and a plurality of hollow fins 4 attached to the chassis 2. The chassis 2 has a plurality of grooves 6. The grooves 6 together with corresponding hollow fins 4 define vapor chambers, which accommodate working fluid 8 therein. In operation, the chassis 2 conductively absorbs heat from a heat-generating device. The working fluid 8 at evaporating ends of the chambers absorbs such heat, and is vaporized. The vapor flows to the hollow fins 4 where it condenses and releases latent heat. The condensed working fluid 8 then returns to the evaporating ends through wicking structures that provide capillary forces. However, convection of the working liquid 8 within the chassis 2 is often poor. As a result, the heat dissipation device cannot adequately dissipate heat from the heat-generating device.
Referring to FIG. 6, another conventional heat dissipation device 10 comprises a metal block 15, a heat pipe 11 and a plurality of parallel fins 12. The metal block 15 is directly mounted on an outer surface of a heat-generating device (not shown). One end of the heat pipe 11 is engaged in an aperture 13 of the metal block 15, and an opposite end of the heat pipe 11 is extended through apertures 14 of the fins 12 to be in intimate thermal contact with the fins 12. However, the thermal contact surface of both ends of the heat pipe is limited. Accordingly, the heat removal capability of the heat dissipation device is frequently not sufficient.
Thus, an improved heat dissipation device which can overcome the above-mentioned problems is strongly desired.
Accordingly, an object of the present invention is to provide a heat dissipation device which incorporates a vapor chamber and a plurality of heat pipes to attain great heat removal capability.
Another object of the present invention is to provide a heat dissipation device having a simple and compact structure.
In order to achieve the objects set out above, a heat dissipation device of the present invention includes a heat sink, a plurality of heat pipes, a frame and a fan. Each heat pipe has a lower first connecting portion and an upper second connecting portion. The heat sink includes a base, and a plurality of parallel fins attached on the base. The base comprises a top plate, and defines a hermetically sealed chamber. A plurality of apertures is defined in one side wall of the base, the apertures receiving the first connecting portions of the heat pipes. A plurality of through holes is transversely defined through the plurality of fins of the heat sink, the through holes receiving the second connecting portions of the heat pipes. The frame includes an upper plate, and two side plates depending from the upper plate. A pair of arms depends from respective opposite ends of a bottom portion of each side plate, the arms securing the frame on the heat sink. In operation, working liquid in the chamber transfers heat to the top plate by phase transition. The working liquid also transfers heat to the second connecting portions of the heat pipes by phase transition.